Minimalistic on-chain cross-game NFT attributes

dylanetaft · December 22, 2021, 10:53pm

I think having an NFT token format standard for games is a neat idea as a concept.

I do not think you should be enforcing as much as you are - like a version. The version could just be an attribute described in the external JSON format if it is needed. Could be byte 0 inside the a uint256/bytes32.
Perhaps attributes can be packed outside of Solidity, described in the JSON format, into a single uint256 or bytes32 in alignment with EVM word size.

Not sure why setting or getting attributes needs more than the token ID - like a player id.

github.com

OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC721/ERC721.sol

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts v4.4.1 (token/ERC721/ERC721.sol)

pragma solidity ^0.8.0;

import "./IERC721.sol";
import "./IERC721Receiver.sol";
import "./extensions/IERC721Metadata.sol";
import "../../utils/Address.sol";
import "../../utils/Context.sol";
import "../../utils/Strings.sol";
import "../../utils/introspection/ERC165.sol";

/**
 * @dev Implementation of https://eips.ethereum.org/EIPS/eip-721[ERC721] Non-Fungible Token Standard, including
 * the Metadata extension, but not including the Enumerable extension, which is available separately as
 * {ERC721Enumerable}.
 */
contract ERC721 is Context, ERC165, IERC721, IERC721Metadata {
    using Address for address;

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ERC721 tokens usually have a map of token ID to Address, given an ID you can find the owner.

Also, ERC721 implements a tokenURI method. You might want a method dedicated to replying back with the JSON URL to describe your attributes, similar methodology?